Abstract
Formation impairment due to fines migration during production continues to cause inflow reduction. Proper fines management can optimise productivity, safeguard facilities and cut down on well maintenance cost. Today’s core flood test limitations keep us away from being capable of limiting or avoiding fracture damage. The limitations include: safety aspects which prevent utilisation of hydrocarbon gas in multiphase fluids in confined laboratories, core sample conditions due to recovery problems, reliability of scaling up to field extent, and so forth. Hence based on such limitations, unique approaches were carried out for damage risk assessments.
This paper presents unique techniques to analyse conditions leading to fracture damage, ability to characterise the damage impact and prediction of well performance. The techniques incorporate a CFD and 3D reservoir simulation packages.
Results suggest that in high permeability sands, the finer the grain size (10-100microns) the lesser the pressure decline rates. When 150 - 200 fines microns were simulated, the declines in pressure were comparatively sharper. The sensitivity of grain size in normal matrix formation is less compared to that found in fractured or very permeable formations as in the letter, higher magnitudes of permeability decline were revealed in which case possible shallow invasion damage mechanisms were likely. Unlike the grain size influence to pressure drop and permeability declines, the simulated fines concentration ranging from 20% to 50% by volume of crude along horizontal direction, did have different impact compared to results of same concentration across the width of the sand body. Water cut sensitivity on the other hand revealed significant permeability drops between 0% and 10% water cut at fixed fines concentration.
In these analyses, solid fines velocities were exclusively being monitored in the multiphase flow and could be distinguished from fluid velocities.
